--
-- VHDL Architecture FACT_FAD_lib.spi_controller.beha
--
-- Created:
--          by - Benjamin Krumm.UNKNOWN (EEPC8)
--          at - 10:37:20 12.04.2010
--
-- using Mentor Graphics HDL Designer(TM) 2009.1 (Build 12)
--
-- modified by Q. Weitzel
--
-------------------------------------------------------------------------------
--
-- modified by Patrick Vogler
-- February 17 2011
-- September 17 2010
--
-- modified to be used as a Microwire interface to control the clock
-- conditioner LMK03000 on the FTM board
--
-- modified July 19 2011 by Patrick Vogler
--
-------------------------------------------------------------------------------

LIBRARY ieee;
USE ieee.std_logic_1164.all;
USE ieee.std_logic_arith.all;
USE ieee.std_logic_unsigned.all;


library ftm_definitions;
USE ftm_definitions.ftm_array_types.all;
USE ftm_definitions.ftm_constants.all;



ENTITY microwire_controller IS
   PORT(
      clk_uwire         : IN     std_logic;              -- sclk
      data_uwire        : OUT    std_logic := '0';       -- mosi
      le_uwire          : OUT    std_logic := '1';       -- Latch Enable = chip select
				
      clk_cond_array    : IN     clk_cond_array_type;    -- data to be loaded
                                                         -- into the clock conditioner
      
      config_start      : IN     std_logic;
      config_ready      : OUT    std_logic := '0'; 
      config_started    : OUT    std_logic := '0'
      );
END microwire_controller ;


ARCHITECTURE beha OF microwire_controller IS
  
  type TYPE_uWire_STATE is (IDLE, LOAD_SHIFT_REG, SHIFT);   
  signal uwire_state        : TYPE_uWire_STATE := IDLE;  
  signal register_count     : integer range 0 to LMK03000_REGISTER_COUNT := 0;
  signal bit_count          : integer range 0 to LMK03000_REGISTER_WIDTH := 0;
  signal shift_reg          : std_logic_vector (LMK03000_REGISTER_WIDTH - 1 downto 0) := (others => '0');

  signal clk_cond_array_update :  clk_cond_array_type := (others => (others => '0'));

    


  
BEGIN
  
  uwire_write_proc: process (clk_uwire)
  begin
    
     if falling_edge(clk_uwire) then
       
       case uwire_state is
         
        when IDLE =>
          
          le_uwire <= '1';
          config_ready <= '1';
          config_started <= '0';
          bit_count <= 0;
          register_count <= 0;
          data_uwire <= '0';
          
          if (config_start = '1') then
            config_ready <= '0';
            uwire_state <=  LOAD_SHIFT_REG; 
          end if;


-------------------------------------------------------------------------------
-- send new data only when settings changed
          
        when LOAD_SHIFT_REG =>

          if (clk_cond_array_update = clk_cond_array) then  -- compare old and new settings
            config_started <= '1';
            uwire_state <= IDLE; -- do nothing if settings didn't change

          else                -- program new (changed !!)  settings to clock conditioner
            bit_count <= 0;
            config_started <= '1';	         
	         shift_reg <= clk_cond_array(register_count) (LMK03000_REGISTER_WIDTH - 1 downto 0);
            register_count <= register_count + 1;
            uwire_state  <= SHIFT;  

          end if;
-------------------------------------------------------------------------------
          

       when SHIFT =>
	       data_uwire  <= shift_reg(LMK03000_REGISTER_WIDTH - 1);
	       le_uwire <= '0';
          shift_reg <= shift_reg(LMK03000_REGISTER_WIDTH - 2 downto 0) & shift_reg(LMK03000_REGISTER_WIDTH - 1);			 
          bit_count <= bit_count + 1;          			 
          if ((bit_count = LMK03000_REGISTER_WIDTH)AND(register_count = LMK03000_REGISTER_COUNT)) then
	         le_uwire <= '1';
		      clk_cond_array_update <= clk_cond_array; -- get a copy of the date for comparison lateron
            uwire_state  <= IDLE;
          elsif ((bit_count =LMK03000_REGISTER_WIDTH )AND(NOT(register_count = LMK03000_REGISTER_COUNT))) then
	         le_uwire <= '1';
            uwire_state  <= LOAD_SHIFT_REG;
          else
            uwire_state  <= SHIFT;
          end if;
          
      end case;      
    end if;
    
  end process  uwire_write_proc;
      
END ARCHITECTURE beha;